Modular metamorphic vehicle

ABSTRACT

A vehicle ( 10 ) comprising a vehicle body, a suspension system coupled to the vehicle body, and a plurality of wheels ( 16 ) coupled to the suspension system comprising at least one pair of wheels, each wheel of the at least one pair of wheels being located on opposite sides of the vehicle. The suspension system comprises a changeable wheel track width for the at least one pair of wheels and the wheel track width is changeable between a narrow wheel track width setting ( 12 ) and a wide wheel track width setting ( 14 ) by pivoting a suspension link ( 18 ) about a vertical axis.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This Application is a Continuation-In-Part of International ApplicationPCT/US2006/032356, filed Aug. 18, 2006, which claims the benefit of U.S.Provisional Application No. 60/709,615, filed Aug. 19, 2005, the contentof both are incorporated herein by this reference in their entirety.

BACKGROUND

The present invention relates to vehicles incorporating computercontrolled suspension operation, electrically driven wheels, andconfigurations for amphibious operation. In particular, the presentinvention relates to rapid deployment vehicles, such as militaryvehicles. The present invention also relates to non-military vehicles(e.g., civilian vehicles, SUVs, aircraft recovery vehicles, firefighting vehicles, agricultural vehicles, forestry vehicles, etc.).

In its battlefield or support role, a modern military vehicle is oftenexpected to have high level of mobility (e.g., the ability to rapidlytraverse a wide range of difficult terrain). In many cases, battles arewon or lost on the effectiveness of military vehicle mobility in bothfighting vehicles and associated logistics vehicles.

There are many conventional design requirements needed to achieve agiven level of vehicle mobility. Substantially comprehensive mobilityanalysis can be conducted (e.g., during the design phases of thevehicle) by computer programs such as the NATO Reference Mobility Model(NRMM) and dynamic modeling software (e.g., DADS, ADAMS, etc.). Despitethese types of programs, the actual mobility levels of wheeled militaryvehicles in service around the world have not increased dramatically formany years.

In recent years, there have been many changes in the world that haveinfluenced both the nature of the battlefront and the needs of militaryforces. Various recognized logistical problems in the rapid deploymentof heavily armored vehicles such as tanks overseas have had an impact onthe traditional heavy armored approach to battle warfare, sometimes infavor of lighter, air-transportable vehicles. For this type of approach,it is useful to have vehicles that are difficult for an enemy to locateand that incorporate high levels of stealth (e.g., the capability todeny the enemy the ability to locate or target a vehicle).

The availability of a portfolio of stealth measures along with advancesin communication, information technologies, and smart remotelydeployable armor-piercing weaponry brings into focus the possibility offielding a hidden stealth force (e.g., a disseminated force ofsmart-weapons-equipped, highly mobile stealth vehicles, capable ofoutrunning, out-maneuvering and destroying a tank force). A stealthforce is useful because it is air transportable and deployable. Thestealth force is deployable almost anywhere in the world within hours,rather than the weeks or months often needed for the deployment of someconventional tank forces. However, in order to perform their functionsfrom a distance, it is advantageous for these more lightly armoredwheeled vehicles and their supply lines to have the capacity to outrunand out-maneuver contemporary battlefield vehicles.

The differences in the nature of the mobility of tracked versus wheeledvehicles is a consideration when determining features of a stealthforce. For example, a tank can force its way through fairly densevegetation and/or covered terrain that may be inaccessible to lighterwheeled vehicles. Accordingly, in order to meet the objectives of remotestealth operations, it is advantageous to improve mobility over roughterrain as well as dense and covered terrain.

The advent of new “enabling technologies” such as active suspension,drive by wire or light (DWL), advanced lightweight materials, new drivesystems, etc. may not, by themselves, be sufficient to achieve thedesired level of mobility in future rapid deployment stealth vehicles.This is because of the limitations imposed by transportabilityconsiderations. For example, despite these technologies, it is stillnecessary to transport a vehicle to its place of deployment. Thisdictates many aspects of the vehicle's design, and can inhibit manydesirable attributes needed for mobility.

In many cases, transportation may be done under the vehicle's ownlocomotion along normal highways, or more commonly by rail, sea-born oraerial transport (e.g., C130 limits). Accordingly, the criteria forhighway operation is similar to civilian vehicles—the vehicle shouldconform to maximum individual axle and gross vehicle weight loadingsappropriate for the highway systems and bridge structures it may bedriven over. Overall height should be such that it can safely pass underbridges and through road tunnels etc., while its maximum length, widthand turning circle should be appropriate for the road systems over whichit may be used. Effectively, this means that a military vehicle, in someinstances, should conform as much as possible to highway regulations,not only in its country of origin, but in all countries that it may beused.

In addition, rail and sea transportation can impose dimensionalconditions on military vehicle design, with rail-tunnel clearanceimposing strict width and height disciplines, which vary from continentto continent. Ships, especially roll-on/roll-off ferries, can alsodefine allowable heights and widths.

For rapid deployment military vehicles, an important transportationcapability is air transport. However, air transportation by heavytransport aircraft imposes not only dimensional constraints on height,width and length, but also places limits on overall weight, individualaxle weights, and also defines, how the axles share the load during theloading/unloading operation. Air transport by helicopter is oftentimesweight dependent. The vehicle should be within the allowable liftcapacity of the helicopter to be transported (a lesser weight extendingthe lift range and ceiling height limits). Because getting the vehicleto its place of deployment is in most cases a pre-condition todeployment itself, compliance with each of the forgoing criteria willnormally limit the potential design of the vehicle for its battlefieldor support role.

Achieving the necessary length of vertical suspension travel in jounceand rebound for certain levels of mobility is useful in designing fast,highly mobile, off-road wheeled vehicles. The practical advantages oflong suspension travel for high-speed operation over rough terrain havebeen demonstrated by vehicles competing in competitive off-road racingevents, where suspension travel as great as 30 inches full jounce tofull rebound is sometimes utilized.

Specially designed tires are often used for off-road operation inconventional systems and vehicles. The tire size can effect off-roadmobility. Larger diameter tires are typically better for off-roadsituations except under certain circumstances such as when the mass ofthe tire itself becomes the limiting factor by reason of inertial andhysteresis effects. With current tire technology and vehicle operatingspeeds, the practical advantages associated with increased tire size areoftentimes not lost until the diameter reaches about 60 inches or more.

The maximum allowable tire diameter is typically considered togetherwith the maximum allowable suspension jounce travel, another parameterwhich can effect vehicle off-road mobility. The limit of allowable rearsuspension vertical or jounce travel is set by the bottom or supportstructure of the containerized load. The height position is set by theheight of the top of the container and the under-bridge clearancerequirements. A compromise is typically determined using computersimulations of vehicle operation over the desired terrains in theappropriate weather conditions.

In addition to compromises between wheel diameter and suspension jouncetravel due to the maximum permissible overall height of the vehicle, asimilar limitation can also apply to other types of military vehicleshaving a lower overall height. For example, the center of gravity of avehicle can be a limitation. At a maximum permitted off-road payload,increasing the rear suspension jounce by raising the vehicle's cargo-bedmay improve mobility over some terrains, but may decrease mobility overother terrains by virtue of its increased propensity to roll-over due tothe increased center of gravity height. Some military vehicles that meetthe above-described transportability requirements provide a balancedcompromise between a number of potentially conflicting parameters inorder to realize the comparatively high level of mobility that hasconventionally been needed. This has been accomplished at least in partdue to the experiences of operation influencing vehicle design as wellas the ability to simulate vehicle dynamic behavior using computermodeling. Despite these compromises, mobility can still be improved.

The successful achievement of long suspension travel is not oftentimesstraightforward, even on vehicles where the primary function isdedicated to off-road racing. The design compromises typically made tothe length of suspension travel for vehicles that require a high levelof off-road mobility, but whose function also incorporates designfeatures for meeting a range of additional requirements, can bechallenging. Such vehicles include SUVs and pick-up trucks, whichadditionally need to meet the practical and legislative requirements ofhighway operation, as well as wheeled military vehicles that also meet avariety of additional specialist functions.

If enough clearance is provided with conventional vehicles to permit theuse of wheels and tires large enough and suspension vertical travel longenough to give the needed high levels of mobility, for example, bymoving the wheels laterally outwards beyond the body width of thevehicle to achieve the necessary space, there still are a number ofother potential problems that are to be addressed. One such problemrelates to the types of suspension linkages suitable for the applicationand that can support a long vertical suspension travel (e.g., perhaps asgreat as one wheel diameter of about 50 inches).

There are various advantages and disadvantages of conventional doubleA-arm, or lateral control arm, independent suspension for off-roadoperation. Because the suspension system pivotal axes are essentially inline with the vehicle's longitudinal axis (depending on the detail ofdesign) there is often little, if any, sensitivity to wheel torquereaction. That is, if braking or drive torque were to be reacted intothe outboard ends of the control arms this, in itself, would not resultin the generation of significant spurious vertical forces causing thevehicle's sprung mass to be raised or lowered at that axle position.However, the effective roll center of a double A-arm suspension is quitelow, sometimes below ground surface level, so the vertical momentdistance to the vehicle's sprung mass center of gravity is greater thanfor other suspension systems, resulting in a propensity to body rollwhen reacting to lateral forces such as in cornering or side slopeoperation. Further, the limited length of the A-arms, which “eat” intothe useable chassis or body width, can limit the suspension travel.Accordingly, such systems are often not good. candidates for use wherelong suspension travel is required. Solid axles, which are commonly usedon medium and heavy trucks, and which comprise a single axle housing anintegral differential and spanning the inside width between wheel pairs,are typically limited with respect to vertical jounce travel bypotential contact with the vehicle's chassis rails or underside of thecargo bed or power source.

Leading and trailing-arm suspension systems are relevant to the designof off-road vehicles because they can achieve the necessary length ofwheel travel without “eating into” the width of the vehicle's hull orunderstructure as compared to more conventional lateral control armsuspension designs. Trailing or leading link suspensions are utilizedfor some off-road operation including tanks and other tracked vehicles.Tank tracks are typically sprocket-driven from a fixed (unsprung)axle-drive, while the leading and/or trailing arm support wheels, whichbear the tank's weight along the track length, are not driven. In thecase of a wheel-driven vehicle using trailing and/or leading-armsuspension, consideration is given to containment or elimination of boththe effects of drive and brake torque reactions, as well as momentsgenerated about the suspension pivotal axes by the longitudinal drivethrust and braking forces. Such reactions are capable of generatingspurious vertical force components, which may be detrimental to suitableoperation of the suspension system, especially with respect to NearConstant Force (NCF) springing.

For highway operation where the extent of vertical suspension travel isgenerally modest in comparison to off-road needs, problems can occurwhen driven axles are combined with leading or, more commonly, trailingarm suspension systems. The generation of spurious vertical forces issometimes pronounced when wheel torque and/or tractive force is high,such as for commercial trucks. The dynamic interaction between wheeltorque reaction or tractive force and spurious force can be problematic,giving rise to wheel hop and transmission judder. In the case of thetrucking industry, the phenomenon is often prevalent and is known as“frame rise.” Frame rise is often attributed to the reaction of axlereaction torque into the suspension trailing arms.

Axle torque reaction causes frame rise when the trailing arm is alignedwith the vehicle's horizontal axis. When the trailing arm is at an angleθ to the truck's horizontal axis, a vertical force component V_(f)=tan(θ)×T_(f), where T_(f) is the tractive force of the axle or wheel.Therefore, if a trailing arm were, for example, at a 45 degree downwardinclination from the truck's horizontal axis, the magnitude of thespurious vertical force generated at the trailing arm's attachment tothe truck's frame would equal the horizontal tractive thrust componentat the same point to propel the truck. This can limit the application ofleading and trailing arm linkages for long suspension travelapplications.

The packaging space to achieve the desired length of suspension traveland wheel diameter as well as the type of suspension linkages used arenot the only factors to be taken into consideration when analyzingvehicle mobility or total vehicle design for future wheeled militaryvehicle operation.

For mobility, there are a number of other design considerations, each ofwhich, if not correctly addressed with the appropriate weighting in abalanced vehicle design, can limit a vehicle's mobility, despite gooddesign practice in other areas. One way to identify these parameters andto quantify their influence over different types of terrain in variousweather conditions is to study the NRMM source code and manuals, and/orto run NRMM simulations. Of course, as one skilled in the art wouldappreciate, other methods may also be used.

In addition to the wheel/tire diameter and length of vertical suspensiontravel already mentioned, some other exemplary vehicle relatedparameters include vehicle weight, individual wheel/axle load at theground, number of wheels/axles, number of driven/braked wheels/axles,tire characteristics/tire pressures, available locomotive power,transmission characteristics and efficiencies, tractive force, underbodyground clearances, front pushbar strength and height, driver's forwardview (vision height above ground), braking capability,vehicle/suspension dynamics, lateral stability, steering/maneuveringcapability, fording/amphibious capability, etc.

In addition to mobility related features and the ability to betransportable by road, rail air and sea, there are a number of otherdesirable features that future highly mobile response vehicles mayincorporate. For example, lightweight construction is a desirablefeature for the transportation of rapid deployment vehicles by C130transport aircraft and/or for helicopter lift. It is also a beneficialfeature for mobility and for vehicle fuel efficiency.

Physical aspects which, when advantageously addressed, are likely toprovide a lighter vehicle weight include designs allowing stresses topass through outermost fibers, maximized separation of outermost fibers,use of shape and shaping advantageously, triangulations rather thancantilevers, use of lightweight materials, use of containers, flatracksor cargo beds as stressed parts of the structure, use of armor/landmineprotection as stressed parts of the structure, identification and use oflight reliable discrete components, avoidance of stress raisers orfatigue prone jointing methods, and avoidance of both weight and cost byeliminating unnecessary components. In order to deny an enemy theability to readily target the vehicle, visual, radar, thermal, andacoustic signatures may be minimized. In addition, it may be desirablefor the vehicle to be able to “kneel down” by reducing its suspensionheight, such that it can align its cargo deck with the cargo deck of aC130 or other transport aircraft to facilitate fast unloading andloading of containerized and flatrack mounted cargos.

It is desirable for the vehicle to protect its occupants and criticalsystems against Nuclear, Biological and Chemical (NBC) weapons attack aswell as Electro-Magnetic Pulse effects. EMP hardening is one aspect ofdesign that is desirable for stealth , operation. This is because anyEMP vulnerability is the one way that an enemy may be able tocollectively neutralize an entire vehicular force without first havingto precisely locate them. EMP weapons include nuclear devices but also arange of possible advanced electromagnetic weapons as well as so calledE-bombs such as Flux Compression Generators (FCGs) which useconventional explosive and electrical systems, and which have thepotential to be manufactured with limited technical capability. It isdesirable for the vehicle and its discrete electronic and communicationsystems to be protected from Electro-Magnetic Interference (EMI),whether from external sources or its own internal systems or on-boardweapons such as directed energy weapons. In addition, it is desirablefor the vehicle to be able to protect its occupants and critical systemsagainst light weapons fire and mine blast. It is also desirable for thevehicle to be able to ford a significant depth of water (typically 60inches).

In view of the foregoing, it would be desirable to provide a highlymobile and maneuverable vehicle incorporating a leading or trailing armsuspension system compensated against torque and spurious vertical forcereactions, and which could adapt its wheel-track, suspension geometry,and cab height from its on-road, air, rail, or sea transportabilitymodes to a wide track and long suspension travel configuration. Thiswould allow the wheels to move up past the vehicle's sides in order toovercome the limitation of suspension movement caused by the presence ofthe body or cargo-bed. It would be desirable to provide a system havinglong off-road suspension with movements of up to about 50 inches ormore, thereby enabling reduced vertical accelerations on the vehicle,occupants and cargo, while traversing severe terrain at high speedsdifficult for vehicles with conventional shorter travel suspensionsystems.

It would further be desirable to provide a vehicle that has the abilityto be lowered between laterally extended wheels when needed. Thisconfiguration is advantageous for several reasons including a reductionin detectability and vulnerability to attack, the lowering of the centerof gravity for improved stability, the grounding of the vehicle to allowheavy recoil weapons, the ability for personnel carried within anarmored personnel carrier module to embark and disembark close to groundlevel, the ability to reduce cargo bed height to align exactly withtransport aircraft decks, and readily permit fast, automated cargotransfer to and from an aircraft.

It would further be desirable to provide a vehicle having the capabilityto lift one or more wheels from the ground to minimize tire drag and/orimprove fuel efficiency when carrying less than a full payload and/or toallow the vehicle to proceed in the event that a wheel or tire suffersdamage. It would also be desirable if the operation of the verticalheight and vertical movement of one or more wheels is manipulated asneeded to cross obstacles such as steps, walls or trenches. It wouldfurther be desirable to configure the vehicle so that the wheel drivetorque of the vehicle could be varied from one side to the other asrequired in order to effect differential torque steering or “skid steer”to steer the vehicle or to augment conventional or Drive by Wire orlight (DWL) steering.

It would further be desirable to provide a vehicle that incorporates DWLtechnology having electrically driven wheels, and/or be of modular “plugand play” construction permitting multiple vehicle configurations forvaried purposes to be assembled from a limited range of common modules,with the reconfiguration of module function primarily by softwarechanges to the vehicle's management and/or control protocols. Thisenables combined driven, steerable and actively suspended axle modulescomplete with central tire inflation (CTI) systems to be integrated withcargo supporting and handling modules, power source and cooling modules,cab modules etc., and arranged in different vehicular layouts. Forexample, 4×4, 6×6, 8×8, 10×10 and/or other vehicle configurations may bebuilt as needed, or even reconfigured by the end user according tofuture needs as they arise. Additionally, such high-level modularityprovides a convenient means to break a larger (8×8 or 10×10) vehicledown into multiple segments for helicopter lift purposes.

It is preferable for the same plug and play modularity and protocols tobe used for powered and unpowered trailers, articulated vehicles,autonomously operated vehicles and “mobility platforms” useable for avariety of vehicles including both logistics, scouting and fightingvehicles.

Modularity results in a benefit of achieving commonality andinterchangeability of components and modular parts across a fleet. Notonly does it reduce the number of replacement parts, either carried onthe mission or available for air-drop, it improves the sacrificial valueof any immobilized vehicles while serving to reduce the cost ofmanufacture by virtue of economy of scale. Further, it serves to reducethe level of personnel training, tools required, and costs to serviceand maintain a fleet.

It would further be desirable to provide a vehicle that incorporates theappropriate design and management of cooling flows, both ventilated (NBCcontaminatable) for primary cooling, and refrigerated or conditioned fornon-contaminatable areas such as for NBC protected personnel areas andareas housing equipment such as open electronic systems that aretypically unsuited to normal decontamination procedures. It would alsobe desirable to provide a vehicle that is furnished with a suspensionsystem of the Near Constant Force type so that rough terrain has minimaldisturbance on the primary mass of the vehicle.

It would also be desirable to provide a suspension that is controlled bya device and/or system that actively controls the ride height and pitchand roll attitude, preferably deriving vehicle primary mass correctiveforces from energy captured from the natural process of traversing theundulating terrain, rather than from extracting energy from thevehicle's power source and thus potentially degrading fuel efficiency.

It would also be desirable to provide the natural frequencies of theunsprung masses of the wheels, tires, and suspension systems to bedampened by a method which at least minimizes corrective forces betweenthe unsprung masses and the vehicle primary mass, thereby reducingspurious force inputs into the primary mass while reducing suspensionscanning and corrective frequencies.

It would be desirable to provide a vehicle that is furnished with a cabmodule that is readily demountable and interchangeable, and has theability for the cab height to be adjustable in operation. It would bedesirable to configure the vehicle cab to be mounted on the front of thevehicle on a height adjustable but common interface with other vehiclesin a class. This enables cab types to be interchangeable without toolsor forklift equipment, so that cabs may be provided and used in a numberof different forms appropriate for the vehicle's intended usage.

There are several types and degrees of armor and mine-blast protection.Less armored cabs can be more spacious and can be furnished with moreglass area to offer better general driver visibility at less cost. Inaddition, less armored cabs typically have a less intimidatingappearance to the populous and can be used for domestic or non-hostileoperations. Further, special purpose cabs may be provided for use withparticular weapons or equipment modules, or for amphibious operation.

Having the cab set low for transportation purposes improves thereduction of visual and radar signatures. For high speeds over roughterrain, it is useful to mount a cab higher for improved forwardvisibility. For displacement amphibious operation the cab represents abuoyant element and the shaped forward portion of the vehicle's bow.Therefore, to improve buoyancy and lower hydrodynamic drag, theundersurfaces of the cab are aligned with the undersurfaces of thevehicle's main lower-hull. For planing amphibious operation, the designlower surfaces of the cab which form the bow of the vehicle can have abearing on the vehicle's planing power requirement and wave heightcapability. Accordingly, it would be desirable to configure theundersurface of the cab to be aligned marginally below the undersurfaceof the main lower-hull to form a planing step.

In view of various problems discussed above, it would be desirable toprovide a leading and/or trailing arm suspension linkage for drivenaxles of off-road vehicles, capable of large vertical displacementwithout generating significant spurious vertical forces as a result ofvehicle tractive thrust. In addition, it would be desirable to provide ashorter suspension travel for highway vehicles.

In view of various problems discussed above, it would be desirable toprovide a highly mobile and maneuverable vehicle which adapts itswheel-track, suspension geometry, and cab height from its on-road, air,rail, or sea transportability modes to a wide track and long suspensiontravel configuration to enable high speed mobility over difficultcross-country terrain. In addition, it would be desirable to provide arapid deployment vehicle incorporating computer controlled suspensionoperation and electrically driven wheels, and/or those used foramphibious operation.

It would be advantageous to provide a system or the like of a typedisclosed in the present application that provides any one or more ofthese or other advantageous features. The present invention furtherrelates to various features and combinations of features shown anddescribed in the disclosed embodiments. Other ways in which the objectsand features of the disclosed embodiments are accomplished will bedescribed in the following specification or will become apparent tothose skilled in the art after they have read this specification. Suchother ways are deemed to fall within the scope of the disclosedembodiments if they fall within the scope of the claims which follow.

SUMMARY

The present invention relates to a suspension system for a vehiclehaving a body, comprising a plurality of wheels couplable to the vehicleand comprising at least one pair of wheels, each wheel of the at leastone pair of wheels positionable on opposite sides of the vehicle whereinat least one wheel is coupled to a motor, and a changeable wheel, trackwidth for the at least one pair of wheels. The changeable wheel trackwidth comprises at least a narrow wheel track width setting and a widewheel track width setting and the wheel track width is changeablebetween the narrow wheel track width setting and the wide wheel trackwidth setting by pivoting a suspension link about a vertical axis.

The present invention also relates to a vehicle, comprising a vehiclebody, a suspension system coupled to the vehicle body, and a pluralityof wheels coupled to the suspension system comprising at least one pairof wheels, each wheel of the at least one pair of wheels being locatedon opposite sides of the vehicle and at least one wheel is coupled to amotor. The suspension system comprises a changeable wheel track widthfor the at least one pair of wheels and the wheel track width ischangeable between a narrow wheel track width setting and a wide wheeltrack width setting by pivoting a suspension link about a vertical axis.

The present invention further relates to a method of configuring achangeable wheel track width suspension system for a vehicle having abody. The method comprises providing a plurality of wheels coupled tothe suspension system, the plurality of wheels comprising at least onepair of wheels, configuring each wheel of the at least one pair ofwheels to be located on opposite sides of the vehicle, providing achangeable wheel track width for the at least one pair of wheels,wherein the changeable wheel track width is configured to comprise anarrow wheel track width setting and a wide wheel track width setting,and configuring the wheel track width to change width by pivoting of asuspension link about a vertical axis.

The present invention further relates to a system for correctingvertical forces in vehicle suspensions, comprising a suspension armcomprising a first end and a second end, a wheel attached at the firstend of the arm by and assembly, and at least two links each comprising afirst and second end having pivotable bearings at each end, the secondends of the at least two links coupled to the second end of thesuspension arm. The first ends of the at least two links are configuredto couple to a sprung mass of a vehicle and a locus of a center of thewheels is constrained to a substantially vertical linear path over arange of suspension travel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a logistics vehicle with acontainer module and cab height and suspension track set for off-roadterrain according to an exemplary embodiment.

FIG. 2 is a front view of a logistics vehicle with wheel track and cabheight set for highway operation according to an exemplary embodiment.

FIG. 3 is a front perspective view of an armored modular cab in alowered position to allow forward weapon deployment and a weapons moduleon a common chassis according to an exemplary embodiment.

FIG. 4 is a front perspective view of a linkage and/or mechanism tocorrect spurious vertical forces in leading and trailing arm vehiclesuspensions according to an exemplary embodiment.

FIG. 5 is a front perspective view of a tuned mass damping systemaccording to an exemplary embodiment.

FIG. 6 is an illustration of an exemplary embodiment of a vehicle havinga suspension system positioned in a narrow wheel track width.

FIG. 7 is an illustration of an exemplary embodiment of a vehicle havinga suspension system positioned in a wide wheel track width.

FIG. 8 is an illustration of a 4-wheel vehicle including an exemplaryembodiment of a suspension system including an electric motor and geardrive mounted on a suspension arm.

FIG. 9 is an illustration of a 4-wheel vehicle including an exemplaryembodiment of a suspension system coupled to each wheel and the vehiclebody.

FIG. 10 is a perspective illustration of a suspension system configuredfor movement of an attached wheel about a vertical axis from one of anarrow wheel track width and a wide wheel track wheel width.

FIG. 11 is an illustration of an exemplary embodiment of a suspensionsystem couple to a vehicle wheel and having a near constant force strut.

FIG. 12 is an illustration of an exemplary embodiment of a 4-wheelvehicle having an angled suspension arm positioned in a wide wheel trackwidth.

FIG. 13 is an illustration of an exemplary embodiment of a 4-wheelvehicle having an angled suspension arm in a narrow wheel track width.

DETAILED DESCRIPTION

Before explaining a number of exemplary embodiments of the invention indetail, it is to be understood that the invention is not limited to thedetails or methodology set forth in the following description orillustrated in the drawings. The invention is capable of otherembodiments or being practiced or carried out in various ways. It isalso to be understood that the phraseology and terminology employedherein is for the purpose of description and should not be regarded aslimiting.

Referring to FIGS. 1-5, according to an exemplary embodiment, a vehicle10 is provided that allows for changing the cab vertical position, thewheel-track width, and/or general suspension geometry. In highwayoperation and during transportation by air, rail or sea, vehicle 10 hasa lowered cab, a standard (e.g., narrow) wheel track width 12 (see FIG.7), and appropriate, fully operable suspension travel and steering. Forrapid operation off-road over difficult cross-country terrain, thevehicle converts to a high cab and wide wheel track width 14 (e.g., suchthat its wheels are set outside its body) such as shown, for example, inFIG. 15). The conversion allows the wheels to move up past the vehicle'ssides, and the limitation of suspension movement caused by the presenceof the body or cargo-bed is obviated. With this system, relatively longoff-road suspension movements of about 30 to 50 inches are madepossible, enabling reduced vertical accelerations on the vehicle andoccupants, while traversing severe terrain at speeds difficult forvehicles with conventional suspension systems. It also permits the useof low or near constant spring force over a large part of thesuspension. At the same time, the increased track width 14 significantlyreduces any tendency for lateral instability (e.g., rolling). Further,the vehicle's body may be lowered between the wheels to enhancestability and/or reduce visual, thermal and radar signatures (e.g.,improve stealth operation).

There are further advantages to being able to lower the body of avehicle closer to the ground. For example, near ground level access forpersonnel transport can be provided without significantly compromisingmobility. In addition, a heavy recoil weapon, such as a howitzer, may beused as a weapons module. The hull of vehicle 10 can be set down incontact with the ground to give the necessary stability and recoilreaction. Within a few seconds of deploying the weapon, vehicle 10 canrise and move to another location, depriving the enemy of any usable fixon the deployment signature. Further, lowering the body of the vehicleallows for a greater ease of handling modules. Because of the reducedattachment deck height, automatic self loading and unloading of modulesof logistical or weapons types is achieved with inherently simpler andlighter systems than current practice dictates.

According to an exemplary embodiment, vehicle 10 comprises a vehiclehull or body, a control or suspension system coupled to vehicle body,and a plurality of wheels 16 coupled to the suspension system. Wheels 16comprise at least one pair of wheels and each wheel 16 of each pair islocated on opposite sides of vehicle 10. The suspension system comprisesa changeable wheel track width for each pair of wheels 16. The wheeltrack width is changeable between a narrow wheel track width setting 12(see FIG. 6) and a wide wheel track width setting 14 (see FIG. 7) bypivoting a suspension link 18 about a vertical axis.

Vehicle 10 comprises a vehicle driver cab that is verticallydisplaceable and has at least one raised position and at least onelowered position. Vehicle 10 comprises a motor 50 dedicated to eachwheel 16 and used to drive the respective wheel. The motor 50 can be,for example, an electric motor or a hydrostatic motor. It is alsocontemplated the motor can be coupled to a shaft extending in thesuspension arm 18 and to an end assembly coupled to a wheel 16. Themotor 50 can also be mounted on the vehicle body and coupled to thewheel 16 with an appropriate linkage, for example shaft, differentialand transmission. The body is configured to be lowered between thewheels 16 on opposite sides of vehicle 10 when wheels 16 are in the widetrack width setting 14.

According to an exemplary embodiment, a suspension system is providedcoupled to wheels 16. The system is configured to enable the changeablewheel track width for each pair of wheels 16. The narrow wheel trackwidth setting 12 is intended to comply with road, rail, sea and airtransportation requirements. The narrow wheel track width setting 12 isconfigured so that wheels 16 are able to travel a first suspendedvertical distance 44 (see FIG. 6). The wide wheel track width setting 14is configured so that wheels 16 extend outward to at least partiallyclear a vehicle body thereby permitting wheels 16 to travel a secondsuspended vertical distance 46 (see FIG. 7). According to an exemplaryembodiment, the second suspended vertical distance 46 is greater thanthe first suspended vertical distance 44.

According to various exemplary embodiments, wheels 16 may beindependently steered by hydraulic, electrical and/or pneumaticactuators controlled by signals from one or more processor. A firsttransducer and/or sensor may be used to determine the steering positionof a steered wheel. The first transducer and/or sensor comprises ananalog device which is automatically calibrated by a second transducerand/or sensor which sends a pulse signal when the steered wheel passes apredetermined steering angle. The first transducer and/or sensor iscalibrated to verify signal integrity and correct for signal drift.

According to an exemplary embodiment, the suspension system comprises amotor dedicated to each wheel 16 and utilized to drive each respectivewheel. Each wheel 16 is partially covered by a housing which moves witheach wheel and is configured to reduce visual, radar and thermalsignatures of the wheels. The wheel 16 may be coupled to the suspensionarm 18 with an assembly 58, for example a planetary reduction drive. Theassembly 58 may include a motor 50 coupled to wheel 16. (See FIGS. 8 and9). The suspension link 18, which may comprise a trailing arm or aleading arm, is configured to attach to a vehicle 10 by pivoting aboutan axis which moves with suspension vertical displacement so thatspurious vertical force resultant from wheel tractive force and angulararm position relative to the ground plane is minimized. The suspensionlink 18 is configured to be constrained in motion by other links (e.g.,similar to a “McPhearson strut” or “semi-trailing” link).

According to an exemplary embodiment, the changeable wheel track widthis held in the narrow wheel track width setting 12 and the wide wheeltrack width setting 14 by links 18 driven by actuators. According to anexemplary embodiment, the changeable wheel track width is held in thenarrow wheel width setting 12 and the wide wheel track width setting 14by actuators moving links 18 directly. The mechanical lock mechanismsare used to lock links 18 in narrow wheel track width setting 12 andwide wheel track width setting 14. The force utilized to change thewheel track width is reduced by a combined use of a wheel steeringmechanism and forward motion of the vehicle so that during a trackwidening change the wheel steering mechanism aligns wheels 16 outwardand during a track narrowing change the wheel steering mechanism alignswheels 16 inward.

According to an exemplary embodiment, vehicle 10 includes a payload thatforms part of a stressed structure of the vehicle. The payload comprisesan ISO container which is modular and attached to the vehicle withcontainer ISO-locks incorporated in the vehicle body. The payload may bea cargo bed module for transportation of cargo and the cargo bed modulemay comprise ISO-locks for attachment of a container module.

According to an exemplary embodiment, vehicle 10 comprises a cab modulewith a standardized mechanical and electrical mounting interface withthe vehicle, the cab module being configured to provide different cabarrangements. According to an exemplary embodiment, the cab module maybe configured for amphibious operation in a floating displacement hullmode by setting cab height relative to the vehicle. Ground clearance forthe cab module is configured by setting cab height relative to thevehicle such that a forward lower part of the vehicle body immediatelyaft of a rear lower edge of the cab module forms a bluff step to reduceinduced rearward velocity of air under the vehicle.

According to an exemplary embodiment, vehicle 10 includes applicationsfor amphibious operation by being able to raise its wheels sufficientlyhigh to expose the vehicle's underbody to the surface of a body ofwater. According to a first exemplary embodiment, amphibious operationoccurs where vehicle 10 raises wheels 16 to an intermediate level sothat the floating hull becomes stabilized laterally by the partiallyimmersed wheels acting as powered, steering and buoyant outriggers.According to a second exemplary embodiment, vehicle 10 raises wheels 16sufficiently to clear the water and uses a planing hull utilizing amarine drive system and a vehicle power to weight ratio in excess ofabout 60 brake horsepower (bhp) per ton.

According to an exemplary embodiment, vehicle 10 comprises a rear hullmodule that houses a marine propulsion system and a dedicated electroniccircuit, motor, cooling device, lubricating fluid, ducting, electricalpower controller, transducer, processor, and/or associated software forinterfacing with a central control system. The marine propulsion systemcomprises a stern drive propeller and/or hydrodynamic water jetthruster. Vehicle 10 comprises an electrical generating devicecomprising an internal combustion engine, a turbine driving anelectrical generator, and/or a fuel cell. The electrical generatingdevice is housed in a power module for providing electrical power to thewheel module and marine propulsion system to enable locomotion of thevehicle.

According to an exemplary embodiment, vehicle 10 comprises a wheelmodule that can include a wheel 16, an associated suspension assemblyelement (e.g., link 18), an associated wheel drive element, anassociated wheel braking element, an associated wheel steering element,and/or an associated central tire inflation element. In addition, thewheel module may comprise an electronic circuit, a cooling device, alubricating fluid, power fluid, ducting, an electrical power controller,transducer, processor, and/or associated software interfacing with acentral control system. One or more of suspension operation, steeringoperation, braking operation, central tire inflation, and driveroperation can be controlled by signals from a common processing center.

In general, off-road rough terrain vehicles fall into two primarycategories including wheeled and tracked. While the general level ofmobility of both categories may overlap and compare favorably with eachother across a wide range of mobility scenarios, each methodology hasvarious advantages and disadvantages for different vehicle applications.

Tracked vehicles can spread their weight over a large ground contactarea, so generally fare more favorably in soft slippery conditions andare usually a preferred choice for heavy armored vehicles. Comparablewheeled vehicles have large wheels and light wheel loadings, with tiresset to low pressure operation by means of a central tire inflationsystem (CTI). Further, heavily armored tracked vehicles, such as tanks,are able to force a path through foliage and lightly wooded areaswhereas lighter vehicles are not always able to do this.

For sustained high-speed travel over paved roads and trails, the wheeledvehicle's capability exceeds that of conventional tracked vehicledesigns, in both speed and maintainability. By not having a restrictionplaced on it by the presence of the tracks themselves, the wheeledvehicle has a greater potential to achieve the design goal of a longsuspension travel, both in absolute terms and also differentiallybetween adjacent wheels on the same side of the vehicle.

The exemplary vehicle enhances the mobility of light and medium weightwheeled vehicles so that they outperform most other conventionalmilitary vehicles in both terms of sustainable speed, not only overpaved roads and trails, but also over a broad spectrum of rough off-roadterrains as well as soft slippery terrain. High vertical accelerationsimposed on the unsprung masses of the wheels of conventional vehicleswhile traversing rough terrain at high speeds can prematurely limit thepotential of the vehicle, if all measures are not taken to reduce theunsprung wheel masses. This is because at these high speeds the verticalinertia component of the wheel mass, which is reacted by the suspensionspring rebound force, may prematurely result in an excessive loss oftire contact with the ground when traversing rough terrain. Becauseconventional vehicles are generally not designed to be fast enough to beimpeded by these tire/ground contact limits, unsprung mass is not asimportant as it is at higher speeds. Therefore, conventional vehiclesnot only incur the unsprung weight penalty of wheel mounted brakes, butoften have heavy reduction drive gearboxes built into their wheels.

Conventional tires are designed to carry higher loads than required forhigh mobility. A 53-inch diameter 16R20 military tire weighs about 330pounds, and is typically rated at a load capacity of about 14,500 poundsper tire. Yet on a high mobility vehicle, such a tire is unlikely to beloaded in excess of 7,500 pounds if the light ground contact pressuresneeded for the mobility targets are maintained. At the same time, suchtires are also speed limited at different tire pressure/deflectioncases, due to heat generation associated with hysteresis in thethickness of the tire carcass. Accordingly, dedicated tires developedfor the high mobility applications provide for a reduction in unsprungmass and an increase in allowable tire operating speed.

Vulnerability to tire damage, whether by simple puncture during normaluse or by enemy action, is a potential weakness of pneumatic tiredwheels for military use. With development, and the latest fibertechnologies, this vulnerability is reduced. CTI systems can detect andmaintain tire pressure against small leaks and, on a multi-wheeledvehicle, any one tire damaged beyond the CTI's auto-inflation capabilityis retracted from use automatically. Run-flat tires, which rely on agreased solid rubber tire mounted on the wheel rim inside the air-spaceof the outer pneumatic tire, have the disadvantage of adding to thevehicle's unsprung mass. In the case of a 16R20 tire, this amounts toabout 200 pounds per wheel. Therefore, according to a preferredembodiment in the case of a high mobility vehicle, a solution is toemploy a rubberized aramid or other advanced fiber inner-bag, more orless in the form of an inner-tube, “vacuumed flat” into a protectiverecess in the wheel rim within the airspace of the tire. The CTI systemthen incorporates a “diverter valve” at the wheel, triggered by localtelemetric communication or by a distinctive pneumatic pulse sent downthe individual tire's inflation line, to inflate the emergency innerbag. Being reinforced and non-elastic, such a bag has the potential tobridge even relatively severe tire damage, such as that inflected bymachine gun fire.

Vehicle 10 can incorporate additional design considerations for rapiddeployment stealth vehicles. For example, noise signature, thermalsignature, nuclear, biological and chemical (NBC) protection,electromagnetic pulse (EMP) protection, radio frequency interference(RFI), and armor protection are technologies associated with enclosuredesign. In addition, lightweight construction is achieved by directingthe stress path around the outermost fibers of a structure—anothercriteria associated with enclosed stressed shell construction.

Within this enclosed environment, the design and management of coolingflows, both ventilated (NBC contaminatable) for primary cooling, andrefrigerated or conditioned for non-contaminatable areas such as forpersonnel and processing equipment, are applicable. Similarly, theprotection and screening of the subsystem electronic communicationchannels are applicable.

The use of individual electric wheel drives frees the design fromlimitations of conventional propeller and axle shaft drive systems. Theprime mover may be a conventional power unit, internal combustion orturbine, driving a generator, a fuel cell, and/or other system.Individual electric wheel drive motors may include a fixed ratio gearingor at least a two step ratio change drive to their respective wheels.This is because the extremely high wheel torques encountered by militaryvehicles over cross-country terrain, especially when hauling unpoweredtrailers, are likely to use larger (diameter), heavier and more costlymotors on a fixed ratio drive than on a multi ratio drive. Further,larger diameter motors are often more limited with respect to a maximumallowable speed due to centrifugal limitations on their armatures orrotors. To determine whether an electric motor is preferred, alternativeconfigurations are compared in terms of size, weight and cost. Whenthese parameters are more favorable in fixed ratio motor, fully meetingboth the low-speed torque requirement and the high speed operatingcapability, then such a motor is be the preferred choice over a smallermotor combined with a simple two-ratio planetary gearbox.

The traversing of rough terrain at high speeds raises the issue of speedvariations imposed on the effective inertial mass of eachwheel/drive-train/motor system, caused by instantaneous differencesbetween the linear speed of the vehicle and the true speed at the tirecontact point. That is, while vehicle 10 may travel at high continuousspeed cross-country, the tires follow the terrain travel at independentand constantly varying speeds. Thus, according to an exemplaryembodiment, constant angular wheel accelerations are reacted against therotational inertia of the wheel and drive system. Because the drivemotor is geared to run at higher rotational speeds than the wheelitself, its effective rotational inertia can in some instances be veryhigh resulting in longitudinal reactions on the vehicle/occupants,dynamic wheel-slippage, and/or significant electrical drive motorsurges. To overcome such problems, an acceptable level of dampedtorsional compliance can be designed into the drive system, or somelevel of longitudinal compliance can be designed into the wheelsuspension system. Other techniques such as electrical power cross-feed,feeding instantaneous power from decelerating wheel drives intoinstantaneously accelerating wheel drives via a small capacitance bankcan also be applied. Such systems can use direct torque sensing at, orclose to the wheel, to cut drive inertia out of the equation.

Trailing arm suspension systems are relevant to the attainment of largevertical suspension displacements because they can achieve the necessarylength of wheel travel without “eating into” the width of vehicle's hullor understructure as significantly as a more conventional lateralcontrol arm suspension. Trailing-arm systems are commonly employed ontanks and other tracked vehicles. However there is a difference betweenthe applications. Tank tracks are typically sprocket-driven from a fixed(unsprung) axle-drive, while the leading or trailing arm support wheels,which bear the tank's weight along the track length, are not driven. Inthe case of a wheel-driven vehicle using trailing or leading-armsuspension, full consideration is given to containment or elimination ofboth the effects of drive and brake torque reactions, as well as momentsgenerated about the suspension pivotal axes by the longitudinal drivethrust and braking forces. Such reactions are capable of generatingspurious vertical force components, which may be detrimental to thecorrect operation of the suspension system, especially with respect toNear Constant Force (NCF) springing.

Spurious vertical forces may be generated as a result of two distinctphysical reasons. First, if the torque reaction of a driven axle orwheel brakes are reacted into a simple leading or trailing arm system,the moments to the same value about the arm pivot will be applied. Thesemoments will be reacted at the suspension spring element, giving rise toa vertical force. This force will be upwards for a driving torque anddownwards for braking on a trailing arm system. Respective forcedirections will be reversed for leading arm systems.

Second, if the arm (e.g., link 18) is not aligned with the horizontallongitudinal plane of the vehicle, then longitudinal driving or brakingthrust forces (tractive forces) imparted to the suspension arms, willgive rise to vertical force components proportional to the longitudinalthrust multiplied by the tangent of the angle of deviation of the armsto the plane.

While the addition of a parallel anti-torque link can eliminate spuriousvertical forces caused by wheel torque, it does not necessarilyeliminate the forces caused by tractive force. This can be a limitationof conventional leading or trailing arm design, whether corrected fortorque reaction or not, and is a natural consequence of the locus of thewheel center following an arc about the arm pivot.

The tangent of the angle of deviation of the suspension arms from thelongitudinal horizontal plane of the vehicle is the same as the ratio ofopposite to adjacent sides of a right triangle whose hypotenuse is aline between the wheel center position when the suspension arm ishorizontal and the wheel center in any other position. Accordingly,there can be an insignificant vertical thrust generated if the adjacentside of the triangle has length of zero. With a conventional leading ortrailing arm, this can typically only occur if the arm has substantiallylong (e.g., infinite) length relative to the vertical travel.

Referring to FIGS. 4, 10, 11 and 12, one embodiment of a suspensionsystem generates a substantially similar effect as an infinite leadingor trailing arm length of conventional systems by means of two links 20,22 interposed between arm 18 and the vehicle's sprung mass, instead of asingle pivotal bearing. Link arm 18 is shown as having a pair of pivotpoints 30, 32 that rotatably couple with pivot points 38, 40 located onlinks 20, 22, respectively. Links 20, 22 then have second pivot points34, 36, respectively, that then couple to the vehicle primary mass andare pivotable around a vertical axis so as to provide for the changeablewheel track width setting. By arranging the arm 18 and links 20, 22 in anominal mid suspension travel position, the wheel center 26 isconstrained to follow an essentially linear vertical locus 24 from fullrebound to full jounce.

Vertical force components of the tractive forces generated by thevehicle drive system or vehicle braking system and reacted upon by thesuspension arm 18 are not transmitted to the sprung mass (vehicle body)through pivot points 34 and 36 of the suspension system. According to anexemplary embodiment, no significant combined spurious vertical forcesare generated at the links 20, 22 attachment to the sprung mass ofvehicle 10.

In an exemplary embodiment, the suspension arm 18 includes an angledportion 54, for example, 30° relative to the unangled portion 56(hereinafter referred to as the morph angle) (See FIG. 12). Theadvantage of the angled suspension arm is to provide a near linearvertical locus of travel of the wheel 16 when the wheel is in the widewheel track width 14 configuration. According to an exemplaryembodiment, there is no specific requirement for symmetry about thehorizontal or vertical axes of either the components or pivotalattachments on the suspension arm 18 or vehicle sprung mass. Inaddition, there is not a requirement for the link arms 20, 22 to be ofequal length. Of course, one skilled in the art can appreciate the abovesystem is merely exemplary and any number of suitable configurations maybe utilized.

Referring to FIG. 11, according to an exemplary embodiment, a nearconstant force strut 52 may be provided with suspension arm 18. Strut 52may be coupled via lever arms extending from the wheel-side ofsuspension arm 18 and one of links 20, 22. Strut 52 may be locatedeither above (if coupled to link 20) or below (if coupled to link 22)the suspension arm 18.

According to an exemplary embodiment, a near constant force, nearisothermal gas spring may be used with vehicle 10. A compact,automatically leveling, high-pressure gas spring having the capabilityof providing a near constant force to a trailing or leading armsuspension system over a large vertical suspension travel (up to 50inches) may be provided. Highly nonlinear adiabatic gas expansion andcompression behavior is at least minimized by using a high thermalconductivity metal mesh, sinter or corrugated coil filling within theentrapped gas volume. By doing this, the highly nonlinear dynamicadiabatic temperature changes within the pressurized gas volume are atleast reduced by virtue of the heat transfer between the gas and metalfilling. The effect is to reduce the gas characteristics to nearisothermal behavior, which, for example, can cut the pressure rise for agiven volumetric compression value almost in half. The remainingnon-constant-force isothermal-like gas behavior is then made to functionas near-constant-force by arranging the connecting link mechanism togive a changing mechanical advantage to correct the force applied to thesuspension movement to the desired near-constant-force behavior. Afeature of this approach is the use of a simple, compact, diaphragm pumpwhich has a direct hydraulic fluid/gas interface directly across thediaphragm, to fulfill the self-leveling function. This eliminates theweight, cost and packaging bulk of multiple high-pressure accumulators.

According to an exemplary embodiment, antiphased tuned mass damping (seeFIG. 5), also known as tuned mass damping (TMD) or inertia damping, maybe used in vibration mitigation. For example, a TMD cylinder 28 mayinclude a relatively small mass (between 1-7% of the primary mass) thatis set on one or more spring elements (not shown) and arranged tovibrate at, or close to the natural frequency of primary mass (e.g., thewheel, tire, suspension system, etc.), shown as vehicle wheel assembly42, to be damped. The small tuned mass is lightly damped against theprimary mass which causes it to vibrate out of phase with the primarymass and, oftentimes, at an amplitude of vibration greater than theprimary mass. Accordingly, the forces from the small tuned mass tend tocancel the vibration of the primary mass. This feature can be utilizedto limit the amplitude of the “wheel bounce” frequencies of the unsprungmasses of off road vehicle wheel assemblies (e.g., where a long travelnear constant force suspension and active control system such as whereActive Suspension by Timed Intermittent Connectivity (ASTIC) are used).

The wheel (bounce) damping function, can be addressed in several ways.For example, conventional damping techniques within the strut or via aconventional damper may be used. In addition, damping wheel-hop bydriving the strut servo valves via algorithms which recognize thewheel-mass/tire natural frequency for any given CTI setting may be used.According to a preferred embodiment, the technique of anti-phased tunedmass damping, which draws on the principles successfully employed in thedamping of the natural frequency oscillations of skyscraper buildingsmay be utilized.

The problem with attempting some conventional damping systems withmilitary vehicles is that the Central Tire Inflation (CTI) system isused to vary tire pressures significantly in operation. This changes thenatural frequency of the unsprung masses. To overcome this limitation,small air springs may be used to constrain the tuned mass, inflated tothe same pressure as the tires by the CTI system. This would tend toautomatically match the natural frequencies of the systems with tirepressure changes.

According to an exemplary embodiment, a “tuned impact damper” may beused. This is similar to the tuned mass damper, but the mass is free tohammer between two resilient stops. This system has similarities tosystems employed on high-rise buildings and obtains similar results witha smaller tuned mass.

ASTIC is a low stability “sprung” mass control system, which is similarto the zero or negative stability systems used for fighter aircraftcontrol (e.g., X29). Low stability is deliberately achieved by employingnear constant force support elements in each wheel suspension instead ofsprings. Correction of the “sprung” mass (also referred to as theprimary mass) to maintain desired ride-height and angular positions inpitch and roll is achieved by using corrective forces derived from theenergy captured as the vehicle traverses rough or undulating groundsurfaces. This greatly enhances suspension capability without requiringadditional vehicle power, and is of importance to overall fuelefficiency of the vehicle.

Computing the corrective forces and moments and applying a controllingstrategy permits one or more chosen strut to be partially or completelylocked. Releasing or locking a strut is timed such that the measuredforce, over and above the near constant force (NCF) value, is appliedfor a real-time computed duration suitable to achieve the correctiveaction. In this way, locking the suspension captures energy moving theprimary mass in the desired direction. Unlocking the suspensiondecouples energy moving the primary mass an undesired direction.

Having completed a control cycle, the primary mass will closelyapproximate the targeted set-point values. A new corrective cycle willrepeat the process thus achieving active suspension control. Inoperation, this suspension control provides improved ride quality, evenfor changing load and terrain conditions. In addition, the primary masspitch, roll and ride height can adjusted to optimize missionrequirements,

“Drive by Wire or Light” (DWL) adds a dimension to military vehicledesign. A DWL system functions by using a computer or processor tointerpret the operator's commands and control the vehicle's subsystemsby means of digital signals communicated along wires or optical fiberleads. For example, a steering input from the driver may be processed,using specially written software, to provide separate signals toservo-motors or actuators at each wheel, changing the steering angle ofeach wheel individually to effect a properly executed turn. According toan exemplary embodiment, there is no mechanical linkage between thewheels, there is no compromising physical limitation on the steeringangle relationship between individual wheels. Accordingly, differentoptimal steering angle relationships may be defined by the computer,depending on the vehicle's speed, payload configuration and terrainsurface conditions. In some circumstances, such as tight turns inslippery conditions, the controlling algorithms can elect to vary wheeldrive torque between wheels on opposite sides of the vehicle to helpexecute the driver's commands.

As discussed above, with respect to DWL systems, reliability ofoperation for multiple individually steered wheels is achieved usingautomatically-calibrating analog wheel steering angle sensors. Thistechnique comprises a highly reliable analog angular position sensorusing, for example, a strain-gauged element operating well below itsendurance limit. Continuous calibration of the sensor to prevent driftis accomplished using a second simple pulse sensor at the steered wheel,such as a Hall effect sensor, to trigger at the “dead ahead” position.The pulse, which is transmitted from each of the steered wheels everytime the dead ahead position is crossed, is used to recalibrate thatwheel's steering sensor's output. Since this happens many times a minutein normal use, wheel alignment of multiple wheel systems isaccomplished. This technique also fulfils the role of double redundancyin the steering signal communication, while at the same time permittingthe use of inexpensive, but highly reliable, analog positioningtransducers with the precision of an encoder. According to an exemplaryembodiment, the system is configured so that if a wheel steering sensoror actuator malfunction, the error is detected, the driver warned, andthe affected wheel lifted out of use.

According to various alternative embodiments, DWL may be applied to avariety of other vehicle control parameters such as active suspension,steering, wheel drive torque, central tire inflation (CTI) pressure,wheel slip control, braking etc. According to an exemplary embodiment,the weapons systems may be integrated with the vehicle control systems.

DWL is an “enabling technology” for modularization. It provides a “plugand play” dimension to vehicle design. Under this regime, it is possibleto place the same steered, driven, braked, actively suspended, CTIequipped and track changing lower-hull/axle modules where needed for aparticular vehicle application, without having to “design” andmanufacture the connecting infrastructure. A software change enables aplurality of changes to be made for the axle modules in order tofunction as an individual optimally designed vehicle. Thus, a completefamily of vehicles, including a 4×4 light logistics truck, a 6×6 mediumtruck, fighting vehicles, 8×8 or 10×10 heavyweights, and an associatedrange of powered trailers, can be produced from a single lower-hull/axlemodule design. The complete vehicle lower-hull is formed from anassembly of axle modules and matching “spacer” modules connectedtogether such that the axle loads are suitably distributed. Theprime-mover/generator module and cooling modules form part of theupper-hull. This modularity provides practical vehiclemanufacturability, increased capital and lowered operating cost, as wellas improved operational serviceability.

Versatility for a particular vehicle configuration is reached by furthertaking a modular approach to the cab and payload attachment to the basicvehicle's lower-hull. For logistics applications, the empty vehicleweight can be minimized by not having a cargo-bed as part of the vehicleitself. Instead, the lower-hull is fitted with special pre-tensioningcontainer ISO-locks, such that a full-length container. When carried,this forms part of the vehicle's stressed structure. With a dedicated20-foot container vehicle for example, the action of omitting the cargobed alone yields in excess of 3,500 pounds of extra usable cargocapacity. Lower-hull structural savings further increase the payloadcapacity. Thus, when the vehicle is carrying a load its combinedstructure is stressed to react correctly, and when it is not carrying aload it does not utilize the same structural strength. With loose cargo,the cargo bed itself locks down to the lower-hull's ISO-locks to form acombined stressed structure capable of reacting the full imposed loads.With alternate mixed cargos of full-length or two or three part lengthcontainers, or loose payloads, the stressed cargo bed remains in placeand the containers lock to the cargo-bed.

Essentially the same lower hull, prime-mover/generator and coolingmodules form the base of the combat-vehicle variants. The modular combatvehicle payload also attaches to the lower-hull by means of thepre-tensioned ISO-lock attachments and form part of the vehicle'sstressed structure. Vehicles may also be fitted with an automatic rearmodule self loading-unloading system. Combat vehicles may utilize a widediversity of modules, ranging from Armored Personnel modules at one endof the scale to Rocket systems and Directed Energy Weapons modules atthe other end of the scale.

In concert with the modular approach to the payload, the vehicle cabmounted to the front face of the hull is also modularized and has acommon interface with all vehicles. This is because the cab may comprisea number of different forms. There are several types and degrees ofarmor and mine-blast protection that may be used, and since weightdirectly impacts mobility, heavily armored cabs are preferably of aminimum size compared with the more lightly armored or unarmoredvarieties. Moreover, special purpose cabs may be required for use withparticular weapons, equipment modules, or for amphibious operation.

It is often advantageous for off-road mobility at high speeds over roughterrain that the driver be mounted as high as possible for good forwardvisibility. The ability to lower the cab is useful for transportationpurposes as well as minimizing visual and radar signatures. There arealso several other reasons for the operator being able to select theheight of the cab. For displacement amphibious operation, the cabrepresents a buoyant element and the shaped forward portion of thevehicle's bow. Therefore, to improve buoyancy and minimize hydrodynamicdrag, the undersurfaces of the cab are aligned with the undersurfaces ofthe vehicle's main lower-hull. For planing amphibious operation, thedesign lower surfaces of the cab which form the bow of the vehicle havea bearing on the vehicle's planing power requirement and wave heightcapability. Accordingly, the undersurface can be aligned marginallybelow the main lower-hull's undersurface to form a planing step.Further, in some desert operations, a vehicle's dust trail signature cancause the vehicle to be spotted, especially from the air. Dust-trailsignatures can be minimized by using a forward undersurface air-dam suchas exposing the bluff forward edge of the lower-hull (to act as thedam). The front and rear suspension heights are simultaneously be set toalign the undersurface angle and height relative to the ground tominimize dust disturbance and pick-up. Further, a cab which can belowered at will, especially on-the-fly, extends the field of fire ofrear module mounted weapons systems over the top of the cab to cover thecritical area forward of the vehicle's direction of travel.

According to various exemplary embodiments, the assemblies andcomponents of the vehicle and systems may be constructed from variousdifferent materials. According to a preferred embodiment, the assembliesand components of the vehicle are constructed from materials that aredurable such as metal, alloys, steel, composites, and/or any othersuitable materials. In addition, various parts of the vehicle andsystems may be constructed and assembled as a single integrally formedpiece or may be assembled and constructed from multiple parts.

It is important to note that the above-described embodiments areillustrative only. Although the invention has been described inconjunction with specific embodiments thereof, those skilled in the artwill appreciate that numerous modifications are possible withoutmaterially departing from the novel teachings and advantages of thesubject matter described herein. For example, different types ofvehicles may be used with the systems described herein. In addition, anysuitable number of wheels and/or pairs of wheels may be used (e.g., one,three, five, etc.). Accordingly, these and all other such modificationsare intended to be included within the scope of the present invention asdefined in the appended claims. The order or sequence of any process ormethod steps may be varied or re-sequenced according to alternativeembodiments. In the claims, any means-plus-function clause is intendedto cover the structures described herein as performing the recitedfunction and not only structural equivalents but also equivalentstructures. Other substitutions, modifications, changes and omissionsmay be made in the design, operating conditions and arrangements of thepreferred and other exemplary embodiments without departing from thespirit of the present invention.

For purposes of this disclosure, the term “coupled” means the joining oftwo components (electrical or mechanical) directly or indirectly to oneanother. Such joining may be stationary in nature or movable in nature.Such joining may be achieved with the two components (electrical ormechanical) and any additional intermediate members being integrallyformed as a single unitary body with one another or with the twocomponents or the two components and any additional member beingattached to one another. Such joining may be permanent in nature oralternatively may be removable or releasable in nature.

1. A suspension system for a vehicle having a body, comprising: aplurality of wheels coupled to the vehicle and comprising at least onepair of wheels, each wheel of the at least one pair of wheelspositionable on opposite sides of the vehicle wherein at least one wheelis driven by a motor; a changeable wheel track width for the at leastone pair of wheels; wherein the changeable wheel track width comprisesat least a narrow wheel track width setting and a wide wheel track widthsetting; and wherein the wheel track width is changeable between thenarrow wheel track width setting and the wide wheel track width settingby pivoting a suspension link about a vertical axis.
 2. The system ofclaim 1, wherein the narrow wheel track width setting is configured sothat the wheels are able to travel a first suspended vertical distance.3. The system of claim 2, wherein the wide wheel track width setting isconfigured so that the wheels extend to at least partially clear thevehicle body to permit the wheels to travel a second suspended verticaldistance.
 4. The system of claim 3, wherein the second suspendedvertical distance is greater than the first suspended vertical distance.5. The system of claim 1, wherein the suspension link is at least one ofa trailing and leading suspension arm.
 6. The system of claim 1, whereinthe suspension link is configured to attach to the vehicle by pivotingabout an axis which moves with suspension vertical displacement so thatspurious vertical force resultant from wheel tractive force and angulararm position relative to the ground plane is minimized.
 7. The system ofclaim 6, wherein the suspension link is configured to be constrained inmotion.
 8. The system of claim 1, wherein the changeable wheel trackwidth is held in the narrow wheel track width setting and the wide wheeltrack width setting by links driven by actuators.
 9. The system of claim8, wherein the changeable wheel track width is held in the narrow wheeltrack width setting and the wide wheel track width setting by actuatorsmoving the links directly, and wherein mechanical lock mechanisms areused to lock the links in the narrow wheel track width setting and thewide wheel track width setting.
 10. The system of claim 9, wherein theforce utilized to change wheel track width is reduced by a combined useof a wheel steering mechanism and forward motion of the vehicle, so thatduring a track widening change the wheel steering mechanism aligns thewheels outward and during a track narrowing change the wheel steeringmechanism aligns the wheels inward.
 11. The system of claim 1, furthercomprising: a suspension arm comprising a first end and a second end; awheel attached at the first end of the arm by an assembly; at least twolinks each comprising a first and second end having pivotable bearingsat each end, the second ends of the at least two links coupled to thesecond end of the suspension arm; wherein the first ends of the at leasttwo links are configured to couple to a sprung mass of the vehicle; andwherein a locus of a center of the wheels is constrained to asubstantially vertical linear path over a range of suspension travel.12. The system of claim 11, further comprising: a strut having first endcoupled to the suspension arm and a second end coupled to one of thelinks.
 13. The system of claim 12, wherein the strut is configured as aconstant force strut.
 14. The system of claim 11, wherein the assemblyinclude a planetary reduction drive coupled to the wheel.
 15. The systemof claim 1, wherein each wheel is independently steerable.
 16. Thesystem of claim 11, wherein the suspension arm includes an angledportion and an unangled portion.
 17. The system of claim 16, wherein theangled portion is aligned parallel to the longitudinal axis of thevehicle body when the wheel is at the wide wheel track width setting.18. A vehicle, comprising: a vehicle body; a suspension system coupledto the vehicle body; a plurality of wheels coupled to the suspensionsystem comprising at least one pair of wheels, each wheel of the atleast one pair of wheels being located on opposite sides of the vehiclewherein at least one wheel is driven by a motor; wherein the suspensionsystem comprises a changeable wheel track width for the at least onepair of wheels; and wherein the wheel track width is changeable betweena narrow wheel track width setting and a wide wheel track width settingby pivoting a suspension link about a vertical axis.
 19. The vehicle ofclaim 18, wherein the vehicle body is configured to be lowered betweenthe wheels on opposite sides of the vehicle when the wheels are in thewide track width setting.
 20. The system of claim 18, furthercomprising: a suspension arm comprising a first end and a second end; awheel attached at the first end of the arm by an assembly; at least twolinks each comprising a first and second end having pivotable bearingsat each end, the second ends of the at least two links coupled to thesecond end of the suspension arm; wherein the first ends of the at leasttwo links are configured to couple to a sprung mass of the vehicle; andwherein a locus of a center of the wheels is constrained to asubstantially vertical linear path over a range of suspension travel.21. The system of claim 20, further comprising: a strut having a firstend coupled to the suspension arm and a second end coupled to one of thelinks.
 22. The system of claim 21, wherein the strut is configured as aconstant force strut.
 23. The system of claim 20 wherein the assemblyincludes a planetary reduction drive coupled to the wheel.
 24. Thesystem of claim 18, wherein each wheel is independently steerable. 25.The system of claim 20, wherein the suspension arm includes an angledportion and an unangled portion.
 26. The system of claim 25, wherein theangled portion is aligned parallel to the longitudinal axis of thevehicle body when the wheel is at the wide wheel track width setting.27. A system for correcting vertical forces in vehicle suspensions,comprising: a suspension arm comprising a first end and a second end; awheel attached at the first end of the arm by an assembly; at least twolinks each comprising a first and second end having pivotable bearingsat each end, the second ends of the at least two links coupled to thesecond end of the suspension arm; wherein the first ends of the at leasttwo links are configured to couple to a sprung mass of a vehicle; andwherein a locus of a center of the wheels is constrained to asubstantially vertical linear path over a range of suspension travel.28. The system of claim 27, wherein the assembly comprises a rotatableaxle shaft.
 29. The system of claim 27, wherein the assembly comprises abearing assembly.
 30. The system of claim 27, further comprising: astrut having first end coupled to the suspension arm and a second endcoupled to one of the links.
 31. The system of claim 30, wherein thestrut is configured as a constant force strut.
 32. The system of claim27 wherein the assembly includes a planetary reduction drive coupled tothe wheel.
 33. The system of claim 27, wherein each wheel isindependently steerable.
 34. The system of claim 27, wherein thesuspension arm includes an angled portion and an unangled portion. 35.The system of claim 34, wherein the angled portion is aligned parallelto the longitudinal axis of the vehicle body when the wheel is at thewide wheel track width setting.